Study of oil-rich coal pyrolysis over cerium-modified magnetic core-shell HZSM-5

Oil-rich coal is a valuable resource that possesses properties of oil, and gas. Catalytic pyrolysis is an important method for achieving green and low-carbon development of oil-rich coal. However, the development and research of highly efficient recyclable catalysts still face significant challenges. This study utilized HZSM-5@SiO₂@MgFe₂O₄ (HSMF) as the raw material and employed the hydrothermal method and alkali modification to prepare HZSM-5@SiO₂@MgFe₂O₄ (mHSMF) with a hierarchical pore structure. Subsequently, cerium-modified mHSMF (5-CeO₂/mHSMF) was prepared through the precipitation method. The fixed bed reactor was utilized to investigate the regulatory effect of 5-CeO₂/mHSMF on the pyrolysis products of Shenfu oil-rich coal and its anti-coking performance. The results demonstrate that CeO₂ modification aids in the formation of a micro-mesoporous hierarchical channel structure on the surface of HSMF. The reaction was carried out on 5-CeO₂/mHSMF catalyst at 650 °C in N₂ atmosphere for 1 h, the yield of Shenfu oil-rich coal tar reaches 13.38%, which is up to 176% of the tar yield in Gray-King assay of shenfu coal. Furthermore, compared to raw coal pyrolysis, catalytic pyrolysis of aliphatic hydrocarbons and benzene in tar leads to a 3.04% and 3.07% increase in the content of similar compounds, respectively. Additionally, the H₂ and CH₄ contents in the coal gas increase by 10.49%. After modification with CeO₂, the catalyst exhibits an 86.1% increase in anti-coking performance, with a coke amount of only 11.60 mg/g-catalyst. Moreover, the carbon deposit tends to form a stable graphitized structure. 5-CeO₂/mHSMF exhibits a noteworthy influence on the distribution and composition of Shenfu oil-rich catalytic pyrolysis products. It also demonstrates favorable characteristics such as effective prevention of carbon deposition and magnetic recyclability.